A telecommunication network may provide a variety of services for users of the network. One such service is a voice-activated-dialing (VAD) service, according to which a user may call into a special network entity (e.g., a VAD server) and speak a name or number to be dialed, and the network entity may then initiate the call (or cause the call to be initiated).
For instance, a user operating a subscriber terminal (e.g., a telephone) may dial the telephone number of a VAD server and may then speak a phrase so as to initiate a call. The user may, for example, speak the phrase, “Call John Smith.” In response, the VAD server may consult a stored contact list associated with the user to determine the telephone number or other network address of John Smith, and the VAD server may then initiate (or cause to be initiated) a call to that number of address. For instance, the VAD server may itself place a call to John Smith and may then tic that call together with the user's call, via a conference bridge.
Alternatively, the VAD server may signal to a telecommunications switch in a way that instructs the switch to set up a call with John Smith and to connect the call with the user. (The switch may, for instance, apply well known ISUP signaling techniques to accomplish this call setup.)
Alternatively, as another example, the user might call the VAD server and then speak the phrase “Dial 555-1234.” The VAD server may recognize the word “Dial” and the succeeding digits and may then responsively initiate a call to those digits and connect the call to the user.
Conventionally, a VAD server may employ a speech-recognition module, which is typically arranged to receive speech signals and to recognize speech patterns in the signals by comparison to predefined speech patterns stored in a reference database. The speech patterns stored in the reference database may represent the most common phrases encountered in a given language, for instance, and therefore represent the phrases that are likely to be detected in speech signals received from users.
The subscriber terminal that a user employs to contact a VAD server or other such entity could take any of a variety of forms. By way of example, the subscriber terminal could be a landline terminal (e.g., fixed telephone) or a wireless terminal (e.g., a cellular telephone or other mobile station). Typically, the subscriber terminal will be arranged to access a telecommunications network, e.g., via a local switch, which may then function to couple the subscriber terminal with the VAD server. For instance, in a typical cellular radio-frequency communications network, a mobile station may communicate via an air interface with a base transceiver substation (BTS) at the core of a cell, and the BTS may then convey signals from the mobile station to a base station controller (BSC) and in turn to a mobile switching center (MSC). Upon receipt of a request from the mobile station, the MSC may set up and establish a call path between the mobile station and a port on the VAD server.
A wireless subscriber terminal, for instance, will usually include a user interface including a numeric keypad, a “Talk” (or “Send”) button, an “End” button, and other controls. Separate controls are thus typically provided to enable a user to initiate calls, place calls and/or activate various subscriber services. Modem wireless subscriber terminals also usually include an alphanumeric display suitable for displaying digits that a user is dialing and for displaying a variety of information and messages.
Conveniently, a mobile station can be mounted or otherwise provided in a vehicle, such as a car, truck, aircraft, sea vessel or other entity arranged to be controlled by and to transport a human. For instance, in-car cellular telephones have become commonplace. While driving a car, a person can therefore initiate and receive calls on a cellular telephone. One such call may be a call to a VAD server, for example.
Unfortunately, however, using a wireless subscriber terminal while driving a car or other vehicle can sometimes be dangerous. In particular, where the subscriber terminal requires the user to press a variety of keys (e.g., a sequence of keys) to accomplish a variety of functions (e.g., to dial a telephone number), the user may be forced to look at the subscriber terminal to find the appropriate keys. Further, while talking on a subscriber terminal, the user may be forced to hold the terminal in one hand, thus leaving only the user's other hand to control the vehicle. As a result, a driver can lose control of the vehicle, which can lead to injury.
In an effort to alleviate this problem, hands-free units have been developed for use with wireless subscriber terminals in vehicles. In a common arrangement, for instance, a hands free unit may include a microphone and speaker (or may employ the existing speaker system in the vehicle), and the unit may then include a connector configured to be connected to cellular telephone (e.g., by sitting the telephone in a cradle). The connector typically provides a power source to the telephone and includes audio line-in and line-out functions so as to facilitate feeding speech signals from the microphone to the telephone and feeding speech signals from the telephone to the speaker.
While this arrangement may work to reduce a driver's interaction with a telephone while driving, it may still require the driver to initially dial a telephone number. For at least this reason, a more robust solution is desired.